The relation between pain of capillary blood sampling and lancet diameter was studied in 52 healthy subjects. The tips of six fingers were pricked with a Softclix(R) II lancing device using lancets with identical facet geometry but needle diameters of 0.3, 0.4 and 0.8 mm. Two penetration depths (0.9 and 1.2 mm) were applied. Pain intensity and blood volume were recorded.At a puncture depth of 0.9 mm, pain did not differ between the three lancets. Pain increased with penetration depth, and at 1.2 mm the thicker lancets were somewhat more painful than the thinner ones. Blood volumes increased with lancet diameter and penetration depth. If the pain for punctures providing just enough blood for a glucose test (>/=10 µl) was compared, there was no difference between the lancets.It can be concluded that lancet diameter is of minor importance for the patient. Copyright 1999 European Federation of Chapters of the International Association for the Study of Pain.